1. Technical Field
The present disclosure relates generally to lighting devices, and more particularly, to illumination modules installable on seat backs of passenger vehicles.
2. Related Art
With most modes of passenger transport including air, rail, and road, the passengers are confined within an enclosed space of the vehicle for the entire duration of the journey. Thus, even the shortest trips leave the passenger with some idle time, which the passenger may occupy with work, leisure, and/or rest. As travel takes place at all hours of the day, sunlight that reaches the interior of the vehicle may be too limited or non-existent for some of these activities. Furthermore, safe movement within the vehicle by both passengers and operator personnel alike may be affected without adequate illumination.
Accordingly, passenger vehicles incorporate a variety of interior lighting features that meet safety and convenience needs. Emergency lighting may be installed along critical escape routes, while general lighting comprised of strategically positioned light fixtures that raise the ambient light level throughout the entirety of vehicle interior may be activated at most times. In order to foster a sense of calm and relaxation, softer lighting, in terms of color and intensity, may be utilized. In an attempt to balance the lighting needs of the aforementioned resting passengers on one hand, and the lighting needs of the active passengers on the other hand, the ambient light levels may be maintained at a sufficiently low level so as to not distract from sleep, while allowing wakeful activities such as reading, playing games, and so forth without much eye strain.
On most nighttime journeys or those journeys that extend into typical sleeping hours at the origin or the destination, general lighting is dimmed or switched off, leaving the interior of the vehicle darkened. Out of necessity or desire, a passenger may decide to remain awake notwithstanding the darkness and continue to read or engage in other activities that require more than a minimal level of illumination. To meet this need, many passenger vehicles, and in particular, mass transit vehicles such as aircraft, incorporate a reading light that shines a focused beam of light to the area occupied by the passenger.
In most passenger aircraft, the reading light is installed overhead in the ceiling of the cabin, underneath the passenger luggage storage compartments. One light is dedicated for each passenger seat, with its aim being preset thereto. In many conventional implementations, the light is not adjustable, though there have been some variations such as those with a ball-and-socket type mechanism and others that allow for multi-directional aiming. The reading light is typically controlled via a button on the armrest or other structure on the seat nearby the passenger. In some variations, the button may be incorporated into an input controller device that is used for interacting with an in-flight entertainment (IFE) system. On older aircraft, and on aircraft with lower interior ceilings, the button to activate and deactivate the overhead reading light may be positioned adjacent thereto.
Notwithstanding its ubiquity, overhead reading lights are deficient on several grounds. Because it is positioned overhead and is distant from the passenger, they remain visible to other passengers despite improvements in highly directional light focusing. Along these lines, despite efforts to limit the dispersion of the light beyond the immediate area of the passenger utilizing it, there still remains a degree of light encroachment upon neighboring passengers. Beyond the undesired impact to nearby passengers, conventional overhead reading lamps controlled by a button that is easily accessible require additional control lines, thereby increasing system complexity. On the other hand, without such controls, switching the light on and off is cumbersome at best. Moreover, overhead space is limited because of the countervailing demands for increased baggage storage space, so there are limitations with respect to the size and configuration of adjustment mechanisms and the like that could otherwise improve the user experience with the overhead reading lights.
Alternatives to overhead reading lamps in aircraft and other transport applications have been developed in response to these deficiencies. One such alternative is an adjustable light fixture that is positioned more closely to the passenger such as on the armrest, the headrest, or other structure of the aircraft that is not overhead. Earlier variations utilized flexible arm that is infinitely adjustable by the passenger. Another variation is disclosed in U.S. Pat. No. 7,909,490 to Chou et al., where an elongated housing enclosing a light pivots between an extended, deployed position and a retracted, stowed position. The apparatus can be mounted to a side of the seat or the head rest, extended over the shoulder of the passenger, and swiveled as desired. It is also possible to mount to the apparatus on the seat back. Although these reading lights have less of an impact on nearby passengers, they still involve a substantial physical interaction in stowage and deployment. The articulation and pivoting mechanisms can become degraded and loosened through extended usage, thereby limiting the capability to hold or maintain desired positions. Depending on the mounting position, these reading lights require twisting and reaching by the passenger, and do not represent a substantial improvement beyond conventional overhead reading lights, which can at least be activated with controls accessible nearby.
Thus, there is a need in the art for an improved illumination module that is installable on the seat backs of passenger vehicles, in particular, aircraft. There is also a need for illumination devices that are readily accessible by the passenger, and switched on and switched off with minimal effort within the confines of a passenger seat.